Alternating-current arc-welding apparatus



E. J. WIGGINS AND E SJHEBELER. ALTERNATING CURRENT ARCWELDING APPARATUS.

APPLICATION FILED JUNE 20. I919.

Patented Apr. 4, 1922.

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EDXVARD J. WIGGINS, OF BUFFALO, AND EDWARD S. I-IEBELER, OF "WILLIAMSVILLE, NEW YORK. ASSIGNORS TO FREDERICK W, ALLAN, OF BUFFALO, NEW YORK.

ALTERNATING-CURRENT ARC VVELDING APPARATUS.

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Application filed June 20,

To a?! zchom it may concern:

lie it known that we. Enwann J. VIGGINS and EDWARD S. Hnennnn, citizens of the l nited States, and residing at Buffalo and ll'illiamsville. respectively, in the county of Erie and State of New York, have invented new and useful Improvements in Alternating-Current Arc-\Velding Appa 'atus, of which the following is a specification.

This i vention relates to alternating current electric welding apparatus, and more particularly to apparatus of this character comprising a static transformer for converting polyphase into single phase currents.

Distribution of current from power generating stations is usually made by means of three-phase alternating current, of comparatively high voltage. lVhen it is therefore desired to secure a comparatively low voltage current for use in electric welding or other single phase circuits it is necessary to use either a static transformer or a rotary converter or motor generator. Power com panies, however, do not usually permit the use of a static transformer on one phase of a three-phase circuit, as this tends to unbalance the line. A rotary converter or 1110- tor generator set being comparatively expensive and costly to operate are not satisfactory commercially for use in connection with electric welding or other work circuits consuming a relatively small amount of power.

It is the object of the present invention therefore to provide a static transformer having primary windings connected with a plurality of phases of the power supply line. and a single secondary winding especially arranged for supplying current efficiently to an electric welding circuit requiring only single phase current. By this means the use of machines with moving parts is obviated, and a much better balancing of the line secured than where an ordinary single phase transformer is employed.

In order that the invention may be readily understood, reference is had to the accompanying drawings forming a part of this specification, and in which Figure 1 is a side elevation illustrating more or less conventionally our improved electric welding apparatus comprising a polyphase-single phase transformer, and showing the arrangement of primary and secondary coils thereon;

Figure 2 is a central horizontal section Specification of Letters Patent.

Patented Apr. 4, 1922.

1919. Serial No.'305,6ss.

through the transformer shown in Figure 1, the coils being indicated by dotted lines;

Figure 3 is a diagram illustrating the circuit connections embodied in the transformer shown in Figure 1, in which diagram the primary windings are shown as star connected;

l igurc -it is a view similar to Figure 3 but showing the primary windings as delta connected;

Figures 5 and G are similar diagrams illustrating star and delta connections, respectively, for a slightly modified arrangement of windings.

-icferring to the (lrawings in detail, and more particularly to Figures 1 to 3 thereof, our improved apparatus includes a transformer preferably of the so-called shell type. It comprises a suitable yoke 1, shown as rectangular and having three parallel branches or legs, the middle branch being designated at 2 and the outer branches at It will be understood that this yoke is built up of suitable laminations of soft iron as usual in transformer constructions, and as illustrated in Figure 2.

Three primary windings 0r coils are preferably employed. and these are shown at 4c. 5 and 6. one of these coils being wound around each of the legs of the yoke. One end of the coils is connected with leads 8, 9

and 10 which extend to the power circuit,

and the other ends of the coils are connected to a common conductor 12, thus constituting a star connected primary, as indicated in Figure The middle coil 5 of the primary winding is preferably divided into two sections a and Z), spaced apart and connected by means of a conductor 11, and interposed between these two sections is a single secondary coil or winding 7. The terminals of this secondary coil 7 are attached to leads 13 and 14: connected with electric welding elements comprising a plate or other article 15 and an electrode 16. a current limiting device such as a choke coil 16 being preferably included in the circuit to steady the arc, and prevent excessive flow of current on shortcircuit. While we have specifically mentioned welding, it will of course be understood that our improved apparatus is equally applicable for are cutting or repairing by the electric deposition of metal from the electrode, as is well known.

Itwill be particularly noted that the work circuit is norn'ially open, and that no current flows in the secondary coil 7 except when current is being drawn from the leads 18 and 1%. It will be seen that the yoke provides a plurality of closed magnetic paths, and that the secondary coil, being wound around the central branch or oi the yoke, is so located as to be influenced by the combined flux generated by the three primary coils l, 5 and 6, so that each of these coils contributes to the production oi the current used in the work circuit, connected with the secondary coil, thereby tending to balance the load on the three phases of the power line. Figure l shows how thewindings illustrated in Figure l can be connected in delta. the ends of the coils 4, 5 and 6 being joined by means at conductors 17, 18 and 19.

Figure 5 illustrates a sligh ly modified arrangement of transformer windings, in which a plurality 01": secondary coils are employed. In this figure the primary windings are shown as star connected, and are indicated at d, 5 and 6. Three secondary windings 20, 21 and are en'ip oyed and are also shown as being star connected. 23 and 2% designate the leads of the single phase secondary or work circuit, the lead 23 being connected with the free end of one of the windings, such as 2i, and the lead 2t being connected to the middle point oi? an inductance coil 26 interposed in a conductor connecting the ends of the coils 20 and .t will be noted that in this modification also the work circuit is normally open, and that no current flows in the secondar winding 21 except when being drawn from the loads 23 and 524;.

In Figure 6 we have shown how the windings illustrated in Figure 5 can be delta connected. The primary wii'idings -'.l-, 5 and 6 are united by means oi conductors '11", it and 19 as in Figure d, while the secondary windings are united by conductors 21'', 5 and 29, the leads 2L- and 2t being tapped tr in the winding cl and the inidd'n point o" an inductance joining the windings and 22 as in Figure In the modifications shown in Figures 5 and 6 it will also be noted that all of the primary windings co operate in inducing current in the single secondary or work circuit.

It will be understood, oft course, that suitable taps may be arranged on the sccomlary winding '7 in Figure 1, so as to give diti'erent desired voltages in the work circuit.

What we claim is:

1. Apparatus utilizing polrphase al erna-ting current for metallic arc welding, cutting or repairing by means of a single electrode in addition to the work, including a static transi lor cmiycrtiug polyphasc into single phase currents, said transformer comprising a nmgnetizablc member having a plurality of completely closed magnetic paths, a plurality of primary coils wound thereon, and connected with the polyphasc circuit, and a single secondary coil also wound on said member and dis 30S6tl to our into single phase currents, said transformer comprising a magnetizable member having a number of parallel branches, each branch forming part of a completely closed magnetic path, a polyphase primary circuit comprising windings on a plurality of said branches, and a secondary or work circuit comprising a single coil wound on one olf said branches, the terminals of said work circuit being connected to the arc welding, cutting or repairing electrode and to the work to be Welded, cut or repaired.

3. Apparatus utilizing polyphasc alternating current for metallic arc welding, cutting or repairing by means of a single electrode in addition to the work, including a static transformer for converting polyphase into single phase currents, said transformer comprising a magnetizablc member having a number of parallel branches, each branch forming part of a completely closed magi'ictic path, a polyphase primary circuit comprising a winding on each of said branches, and a single phase sccbndary circuit comprising a coil wound on one 'ot said lHfiLllClltS, the terminals oi. said secondary circuit being connected to the arc welding, cutting or repair-- ing electrode and to the work to be welded. cut or repaired, respectively.

el. An alternating current system l'or utilizing polyphase ctu'rcnts for electric anwelding, cutting or repairing comprising a work circuit having a single pair oi electrodes, the material to be welded, cut or repaired constituting one electrode, and the welding, cutting or repairing material constituting the opposite electrode, a transformer itor supplying single phase current to said work circuit and having a magnctizuble core shaped to provide a plurality of completely closed flux paths, a phirality of pri- 

